Nurses said they wanted acknowledgement they are in trouble. One said: "It's breaking point. The health minister needs to stop toeing the party line of: we are all working hard and we are all coping. The first thing people would appreciate is acknowledgement that we are in trouble."

The knock-on effect of waiting time complaints is said to be having a serious effect on A&E staff morale.

"We are the ones that have to face people and say, 'I'm sorry your 90-year-old mother is still on a trolley at 11 hours'." said the nurse. "You can imagine saying that to somebody time and time again over the space of a few years – how would that make you feel?"

The revelation of deaths resulting from delays in treatment comes after initial findings of a probe by the Regulation Quality and Improvement Authority into a 'major incident' in the Royal on January 8 were revealed on Monday.

The damning findings said staff were under "intolerable pressure".

The day before the major incident was declared, on January 7, a consultant emailed concerns to his bosses, claiming: "The most appalling example was an elderly patient found hanging off the end of a an emergency department trolley with fresh faeces dripping down her legs. This is one of the most disgraceful things I've had the misfortune of witnessing in my entire career."

It led to the Health Minister Edwin Poots having to deny suggestions of a possible 'cover-up' after he said he only became aware of the situation following a radio interview yesterday with a senior health official.

In the interview Medical Director Dr Tony Stevens said the patients had died at the RVH within the last 12 months.

"Specifically, in terms of a contributory factor from people waiting longer than we would like them to be seen, we believe last year there were five patients in the Royal," he said.

When asked to clarify if it was five patients who had died or who had come to harm, he replied: "Some came to harm, some died."

When asked how many of those had died, he replied: "four or five".

Mr Poots told the Assembly yesterday afternoon that the five people who died had been seriously ill. He said he has now asked his officials to identify key areas of concern.

The SDLP's Fearghal McKinney told the minister in the Assembly:"We conclude that either the minister didn't know, or did know about the longer-term pressures when he was making his earlier remarks and therefore the public might be right to suspect that there was at least a disguising of the situation or, at worst, a cover-up."

Alliance's Kieran McCarthy also expressed his shock. He said: "The Health Minister is in denial about the crisis in our hospitals' emergency departments."